[ RadSafe ] News: Reducing radiation emissions

[John Jacobus]

>From another list server.  As noted:
". . . This rule-of-four would inhibit the normally
observed decay patterns by which non-spherical nuclei
throw off energy, usually by emitting gamma rays.  In
fact, in the case of nuclear pyramids it is expected
to result in new and unprecedented decay rules. . . ."



PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics
News Number 789  August 22, 2006  by Phillip F.
Schewe, Ben Stein,
and Davide Castelvecchi        www.aip.org/pnu

SMALLEST PYRAMIDS IN THE UNIVERSE.  French physicists
believe they can solve the mystery behind dozens of
nuclear experiments conducted years ago.  The
experiments, conducted with a variety of detectors,
energies, and colliding nuclear species, left puzzling
results, so puzzling and hard to interpret that many
of the experimenters turned their attention to the
study of highly spinning nuclei, a quite fashionable
subject at the time.  Now, Jerzy Dudek of the
Universite Louis Pasteur (Strasbourg) and his
colleagues at Warsaw University and the Universidad
Autonoma de Madrid claim that the old results can be
explained by arguing that some nuclei, made in the
tempestuous conditions of a sufficiently high-energy
collision, can exist in the form of a tetrahedron or a
octahedron.  Like a pyramid-shaped  methane (CH4)
molecule held together by the electromagnetic force, a
pyramidal nucleus would consist of protons and
neutrons held together by the strong nuclear force. 
Such a nuclear molecule--in effect the smallest
pyramid in the universe--would be only a few fermis
(10^-15 m) on a side and millions of times smaller in
volume than methane molecules.  Just as there are
so-called “magic” nuclei with just the right number of
neutrons and protons that readily form stable
spherical nuclei, so there are expected to be such
magic numbers for forming pyramid nuclei too.  Stable,
in this case, means that the state persists for
10^12 to 10^14 times longer than the typical timescale
for nuclear reactions, namely 10^-21 seconds.
Dudek says that gadolinium-156 and ytterbium-160 are
nuclei very conducive to residing in a stable pyramid
configuration.  Nuclei might exist also in stable
octahedral (diamond) forms also.  These nuclei would
all possess a quantum property not seen before in
nuclei: in the process of filling out an energy-level
diagram for the nucleus, four nucleons of the same
kind (neutrons or protons) could share a single energy
level instead of the customary one or two permitted
nucleons.  This rule-of-four would inhibit the
normally observed decay patterns by which
non-spherical nuclei throw off energy, usually by
emitting gamma rays.  In fact, in the case of nuclear
pyramids it is expected to result in new and
unprecedented decay rules.  This inhibition would
explain the puzzling results of earlier experiments. 
Dudek (Jerzy.Dudek at IReS.in2p3.fr,
33-388-10-6498) and his colleagues plan to test these
ideas in upcoming experiments.  (Dudek et al.,
Physical Review Letters, 18 August 2006)



+++++++++++++++++++
>From an article about physicians doing clinical studies: 

"It was just before an early morning meeting, and I was really trying to get to the bagels, but I couldn't help overhearing a conversation between one of my statistical colleagues and a surgeon.

Statistician: "Oh, so you have already calculated the P value?"

Surgeon: "Yes, I used multinomial logistic regression."

Statistician: "Really? How did you come up with that?"

Surgeon: "Well, I tried each analysis on the SPSS drop-down menus, and that was the one that gave the smallest P value"."

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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